JFormField extension doesn't access $this->element from the constructor

Question

I'm creating my custom Field extending the clasic JFormField like this:

class JFormFieldExtension extends JFormField {

protected $type = 'extension';

// Constructor
public function __construct(\Joomla\CMS\Form\Form $form = null) 
{
    parent::__construct($form);

    JLog::add('************** JFormFieldExtension *****************', JLog::INFO, 'my_comp');
    JLog::add('* CONSTRUCT ====>'.$this->element['name'].'<=====', JLog::INFO, 'my_comp');
}

public function getInput() 
{

    JLog::add('************** JFormFieldExtension *****************', JLog::INFO, 'my_comp');
    JLog::add('* getInput ====>'.$this->element['name'].'<=====', JLog::INFO, 'my_comp');
}

With this code above, I get the following output:

2021-12-27T20:53:48+00:00   INFO 172.18.0.1 my_comp ************** JFormFieldExtension *****************
2021-12-27T20:53:48+00:00   INFO 172.18.0.1 my_comp * CONSTRUCT ====><=====
2021-12-27T20:53:48+00:00   INFO 172.18.0.1 my_comp ************** JFormFieldExtension *****************
2021-12-27T20:53:48+00:00   INFO 172.18.0.1 my_comp * getInput ====>field_name<=====

Question is: Why I get the $this->element['name'] inside the getInput() function, but not inside the __construct() ?

Answer 1

element property is set in field's setup() method. It's normally called by the form. But if you're using the field as a standalone class, you can call it manually.